Reference evapotranspiration (ET0) is an essential parameter for hydrological modeling, irrigation planning and for studying the impacts of climate change on water resources. This work evaluate 20 alternative methods of estimating ET0 in order to adapt them to the climatic context of the 3 mains basins of Senegal where very little climate data is available. The methods of Valiantzas 1, Doorenboss & Pruitt and Penman are the most robust for the estimation of ET0 in this context.

The analyze of the trends of ET0 at the scale of the Senegal, Gambia and Casamance river basins using reanalyze data of NASA/POWER over 1984–2019 shows that ET0 increases significantly in 32% of the Senegal basin and decreases in less than 1% of it. In the Casamance and Gambia basins, the annual ET0 drops by 65% and 18%, respectively. Temperature and relative humidity show an increasing trend over all basins while wind speed and radiation decrease, confirming the so-called "evaporation paradox".

This dataset provides a set of hydrometric indices for about 1500 stations across Africa with daily discharge data. These indices represent mean flow characteristics and extremes (low flows and floods), allowing us to study the long-term evolution of hydrology in Africa and support the modeling efforts that aim at reducing the vulnerability of African countries to hydro-climatic variability.

In the theme Panta Rhei, this paper aims to develop a combined approach of data acquisition and a new semi-distributed non-stationary model taking into account land-use changes to reconstruct and predict annual runoff on an urban catchment in a data-sparse context. We use historical data and deploy a complementary short-term spatially-dense dedicated instrumentation. Applications were conducted on the tropical Mefou catchment (Yaoundé, Cameroon) to assess contributions of sub-catchments.

Socio-economic and hydroclimatic data were integrated in a modeling framework to simulate water resources and demand. We successfully modeled water stress changes in space and time in two basins over the past 40 years, and explained changes in discharge by separating human and hydroclimatic trends. The framework was then applied under 4 combinations of climate and water use scenarios at the 2050 horizon. Results showed that projected water uses are not sustainable under climate change scenarios.